Tool oscillating and positioning system



April 19, 1966 E. KOCH 3,247,357

TOOL OSCILLATING AND POSITIONING SYSTEM Filed Dec. 26, 1963 2Sheets-Sheet I N 3 j R a ww 0H Ni I III! m C w m E 3 m i1 l1 E E |||ll MI111... I mm m..... mm 6 w mm mm on k m 22W QNII\ I B ww mm W mm 9w 0 ammm April 19, 1966 E. KOCH 3,2 7,

TOOL OSCILLA'IING AND POSITIONING SYSTEM Filed Dec. 26, 1963 2Sheets-Sheet 2 FIG. 2

. INVENTOR. 44 EU GENE KO CH AGENT United States Patent 3,247,357 TOOLOSCILLATING AND POSITIONING SYSTEM Eugene Koch, Maplewood, N.J.,assignor to Air Reduction Company, Incorporated, New York, N.Y., acorporation of New York Filed Dec. 26, 1963, Ser. No. 333,447 6 Claims.(Cl. 219-126) This invention to tool oscillating and positioning systemsand more particularly to means and methods for positioning a consumablewelding electrode in a welding machine relatively to a path along whichmolten metal is to be laid down by the electrode and for causing theelectrode to traverse repeatedly or oscillate over said path in order todistribute weld metal evenly over the length of the path in successivelayers that are consolidated into a unitary mass such as a welded seamor a metallic overlay.

The invention is particularly applicable, but not limited, to a seamweld in a gap between generally vertically extending workpiece plates tobe joined by welding, where the plates are relatively thick, requiringthat the electrode be oscillated in the direction of the thicknessdimension of the plates in order to distribute weld material evenly overthe entire area of the seam.

An object of the invention is to facilitate and simplify the operationof centering an oscillatable electrode within its path of travel, as forexample with respect to the thickness dimension of workpiece plates ofgiven thickness.

A related object is to make a welding machine which has an oscillatableelectrode readily adjustable to operate over paths of different length,as for example to operate with workpiece plates of any thickness withina wide range of thicknesses by merely setting a single dial and withoutthe necessity of making any measurements or manipulations, beyond thosemade once and for all in an initial calibration.

Another object is to make readily adjustable the amplitude or length ofswing of the oscillatory motion of the electrode.

Another object is to facilitate the initial calibration of the saidsingle dial whereby further adjustment of the positioning mechanism isreduced to a single setting of the dial to correspond, for example tothe known thickness of the workpiece plates. I

A further object is to simplify and reduce the cost of a mechanism forpositioning and oscillating a tool.

A feature of the invention is an arrangement for mounting upon asingle'pair of guide rods both a positionable motor mount for a motorthat drives the oscillating mechanism and an independently slidablemember for moving the electrode in oscillatory motion, the two devicesbeing capable of limited sliding motion independently of one anotherover the same pair of guide rods without mutual interference.

Another feature is a direct reading dial calibrated to read thethickness of the workpiece plates and so geared as to move theoscillator motor mount half the distance indicated by the dial readingso that, for example, when workpiece plates of any specified thicknessare to be welded, the dial is moved to read the desired thickness,whereby the axis of the electrode is moved so as to arrive at the centerof the thickness dimension of the plates to be welded or the center ofthe desired path of travel of the electrode.

A further feature is a simple means for adjusting the amplitude of theoscillations.

Another feature is a provision for introducing dwell at the extreme endsof the stroke of the oscillating electrode in order to supply extra heatif needed Where the weld bead is deposited in thermal contact with awelding darn such as is usually employed to retain molten material inthe weld gap while the molten material solidifies, particularly as thewelding dam is customarily water-cooled.

Other features, objects and advantages will appear from the followingmore detailed description of an illustrative embodiment of theinvention, which will now be given in conjunction with the accompanyingdrawings.

Features relating to the common mounting of both a positionable motormount and an independently slidable tool moving member upon a singlepair of guide rods as disclosed herein are claimed in a copendingapplication of George R. Turbett, Serial No. 333,467, filed of even dateherewith and assigned to the same assignee as the present application.

In the drawings:

FIG. 1 is a front elevational view, partly broken away, of a portion ofa welding machine embodying the invention;

FIG. 2 is a vertical sectional view, taken along the line 22 in FIG. 1;and

FIG. 3 is a top plan view, partly broken away, of the machine of FIGS. 1and 2.

The invention will be described with reference to an illustrativeembodiment arranged for oscillating a welding electrode in the directionof the thickness dimension of workpiece plates to be Welded together toform a substantially vertical seam, with the purpose of evenlydistributing weld meta-l over the area of the seam. It will beunderstood however that the invention is not limited to the embodimentshown herein.

Referring to the drawings, a framework 20 with an attached fixed arm 66,in a welding machine, is shown supporting a relatively fixed welding dam22, directly attached to arm 66, an adjustable welding darn 24, an upperguide rod 26, a lower guide rod 23 preferably in a common vertical planewith the rod 26, and also a lead screw 30.

A motor mount or carriage 31 is threadedly engaged with the lead screw30 and in addition is slidably mounted upon the rods 26 and 28,preferably having relatively Widely spaced slidable bearings 32 and 34upon one rod, the rod 26 as shown, and a relatively central slidablebearing 3-6 upon the other rod 28. Mounted upon the carriage 31 is amotor 38 having a shaft 40 upon which shaft is mounted an inner cam 42of a pair of cams 42 and 44, in peripheral contact with each other, thecam 44 being an outer or ring cam.

The cams 42 and 44 extend through a clearance opening in a slider 46which is slidably mounted upon the rods 26 and 28 with a relativelycentral slidable bearing 4-8 upon the rod 25 between the bearings 32 and34, and relatively widely spaced slidable bearings 50 and 52 upon therod 28 to either side of the bearing 36. Clearance space is providedbetween the bearing 48 and the bearings 32 and 34, as well as betweenthe bearing 36 and the bearings 50 and 5-2 to permit the desired maximumamplitude of oscillation of the slide 46 which in turn determines themaximum amplitude of oscillation of the tool or welding electrode.Fixedly attached to the slider 46 is an arm 54 from one end portion ofwhich the arc sustaining tip 56 of the electrode extends into the arcregion immediately above the upper edges of the welding dams 22 and 24.

The three-point bearing arrangement both in the mounting of the carriageor motor mount 31 and of the slider 46 gives to each of these twoslidable elements a very stable and smoothly slidable operation, freefrom the likelihood of chattering or jamming. The two relatively widelyspaced bearings of either of these elements upon one guide rod serve asa non-rocking main bearing for that element and the third bearing on theother guide rod serves as an outrider to prevent rotation of the mainbearings about the first guide rod. This arrangement, both in the motormount and in the tool-oscillating slider, is particularly importantduring oscillation.

Cam followers 58 and d adjustably mounted upon the slider 46 arepositioned to make at least intermittent contact with the cam 44, thuscoupling together the carriage 31 and the slider 46 so that when themotor 38 rotates, motion is transmitted by way of the shaft 40, the cams42 and 44, and one or the other of a pair of cam followers 58 and 60 toproduce reciprocating motion of the slider 46 and of the arm 54 andelectrode tip 6, with any desired amount of end dwell orlost motion.

It will [be evident that, if no end dwell is required, a single camfollower spring-pressed against the cam 44 may be substituted for thepair of oam followers 58 and 60, in well known manner, or if desired,end dwell may be provided by suitable shaping of the cam 44.

The Ilea-d screw 30 runs parallel to the rods 2e and 28 and serves toprovide a means for moving the carriage 3-1 along a line or path oftravel determined by the rods 26 and 28 so that the center ofoscillations of the electrode tip 5'6 may be varied to accommodatedifferent lengths of travel and workpieces of different thicknesses. Aworkpiece plate 62 appears in edge-on view in FIG. 1, together with thecross section of a welded sea-m at 64, the welding dams 22 and 24 inthis figure being shown clamped against the workpiece plate 62 andwelded seam 6 4. It will be evident from this View that if workpieceplates of another thickness are substituted for those shown, thecarriage 31 will have to be moved along its path of travel in order tomaintain the center of oscillations of the electrode tip 56 at thecenter of the thickness dimension of the workpiece plate.

The welding dam 2-2 is shown pivotally attached to the arm 66 which inturn is rigidly attached to the main portion 20 of the framework. Thewelding dam 24 is yieldingly pressed against the workpiece platesthrough a pivotal joint by means of a piston rod 68 and a pneumaticcylinder 70. When the welding dams are clamped against the oppositesides of the workpiece plates a refer ence plane is defined by theworking face of the dam -22 coincident with the faces of the workpieceplates which are pressed against the dam 22. Although the pivotal jointsof the dams 22 and 24 permit a certain amount of adjustment of the damsto irregularities in the workpiece plates, the reference plane sodetermined by the dam 22 represents at all times the average position ofthe adjacent surface of the workpiece plates with respect to theelectrode oscillating mechanism.

Each point in the framework 20 and any equipment attached to theframework has a uniquely defined position with respect to the referenceplane above defined, not only under the conditions existing whenever thewelding apparatus is clamped to a workpiece, but even though the weldingmachine is removed from the workpiece and returned thereto, orthereafter is clamped against another workpiece of different thicknessfrom the first.

The lead screw 30 is turnable manually by means of a geared digital dial72. A stop 74 may be secured to the shaft of the lead screw 39 by meansof a set screw 76 to stop leftward motion of the carriage 31 as viewedin the figure when the electrode tip as reaches the vertical plane ofthe working face of the welding darn 22 at which point the stop 74 canbe arranged to strike some portion of the carriage 31.

The digital reading of the dial 72 may be set to read zero when thecarriage 31 is at such a point that the center of oscillation of theelectrode tip 56 is in the reference plane determined by the workingface of the welding dam 22. The gearing through which the dial 72 drivesthe lead screw 3f) is proportioned so that a reading of one inch on thedial actually represents a carriage displacement of one-half inch fromthe position of the zero reading, and all other dial readings similarlyrepresent carriage displacements from zero position of one-half the dialreading. Thus, if the zero reading is properly set, the dial readingwill always thereafter indicate directly the workpiece thickness aboutwhich the electrode oscillation will automatically be centered.

Illustrative gearing for separably coupling the lead screw 30 to thedial 72 is shown schematically in FIG. 1. It will be evident that otherforms of gearing may be substituted. A spur gear is secured to the righthand end of the lead screw 30 as shown in the figure. An idler gear 81which can be meshed with gear 80* is slidably mounted upon an auxiliaryshaft 82. A gear 83 adjacent to the gear 81 and slid-able therewithalong the shaft 82 can be meshed with a spur gear 84, which is securedto a shaft 85, preferably aligned with the lead screw 30, to which shaft85 the dial 72 is also secured. A collar 86 slidable over the shaft 82and terminated in a button 8-7 is provided to facilitate meshing andunmeshing the gears 81 and 86 from the gears 80 and 84, respectively.Stops, or detents, now shown, may be provided in known manner toposition the gears 81, 83 positively in meshed and unmeshed condition.The button 87 may then be drawn out to mesh the gear train and pushed into unmesh. In the unmeshed condition, dial 72 may be turnedindependently of the lead screw 30.

It will be evident that the gear train 89, 8 1, 83, 84, or equivalent,may readily be so designed that one-half inch travel of the motor mount31 along the lead screw 30 will result in a change in the reading of thedigital dial 72 of one inch.

In terms of displacement of the motor mount, the dial 72 is arranged toindicate displacement, preferably in decimal parts of inches, of themotor mount along its path of travel, with reference to an arbitraryzero displacement, with gearing such as to make the indicateddisplacement twice the actual displacement, and the arbitrary zerodisplacement is made to correspond to a predetermined spacing betweenthe motor mount and the reference plane.

Before describing the initial calibration of the device, reference ismade to indicia in the form of two witness or index marks 90 and 92.These are shown in juxtaposition on the oscillating portion 46 and thenon-oscillating portion 31, respectively, of the electrode oscillatingmechanism. The mark 92 may be a single line or a part of a scale 94 andthe mark 9b may be a line or it may be a finger or pointer projectinginto proximity with the portion of part 31 hearing the scale 94 or indexline 92. The lines may be engraved, stamped, scribed or otherwiseapplied. The indicia are preferably so positioned that elements 90 and92 are in alignment when the member 4d is at the mid-point of its freetravel between the bearings 32 and 34.

To begin the calibration, with the cam followers 58 and 60 retractedfrom contact with the cam 44, the part 31 is moved by means of the dial72 to align the marks 90 and 92, and. the cams 42 and 44 are rotated tothe relative position which corresponds to zero eccentricity and thecentral position of oscillation. Then the cam followers 58 and 60 arebrought into contact with the cam 44 and locked in this position.

The initial calibration of the dial 72 may now be continued as follows.The carriage 31, slider 46 and electrode tip 56 are moved as a unit byturning the dial 72, the motion of the carriage 31 being communicated tothe slider 46 by means of the cam followers 58, 60. This motion is sodirected as to bring the electrode tip into coincidence with thereference plane, to effect the desired zero setting. The coincidence maybe checked by making suitable measurements from the electrode tip 56 toany convenient point in the arm 66 and also from the reference plane tothe same point in the arm 66.

53 With this zero adjustment made, the dail 72 may be set precisely tozero by temporarily disconnecting the digital indicator wheels of thedial from the lead screw 30', as above described, turning these wheelsto zero reading and reconnecting the indicator to the lead screw withoutchanging the rotational position of the lead screw. The calibration isthus completed. The stop 74- may now be set against a portion ofcarriage 31.

An alternative method of calibration will now be described, which willbe preferred in some instances. This method is of the form of an initialadjustment made during assembly of the device. With the motor mount 31and the slider 46 in place on the guide rods 26' and 28 and with themotor mount and slider temporarily locked together by any suitable meanswith the marks 90 and 92 in alignment, and with the electrode tip 56 ora rod in place thereof in operative position, the lead screw 30 may beturned to bring the electrode precisely to the reference plane. This maybe done with or without the dial 72 attached to the shaft 85. Next thedial 72 is removed, set precisely to zero and reattached; or set to zeroand attached for the first time, as the case may be. After attachment ofthe dial so set, the calibration is complete. When this procedure isused, there will generally be no need for a separable connection betweenthe shaft 85 and the lead screw 30, so that the gearing 81, 83 may bepermanently placed and need not be slidable.

Suitable direct reading digital dials for use as hereindescribed areobtainable from Borg Equipment Division, Amphenol-Borg ElectronicsCorporation, under the designation Borg Microdial. Dials of this typeinclude internal gearing and can be attached directly to any suitableshaft, for example lead screw 30, and may be set to zero or any otherdesired dial reading before they are attached to the shaft. Thecombination of the screw pitch of the lead screw 30, the gear ratio, andthe numerical indicia on the dial 72 may be selected to give the desirednumerical relationship between the travel of the member 31 in inches anddecimals thereof, and the digital reading of the dial 72.

Whatever type dial is used, the screw pitch of the lead screw 30, thegear ratio intermediate between the lead screw and the dial, and themarkings on the dial may be so selected as to give the same desirednumerical relationship between tool travel and the change in the dialreading.

When lost motion or end dwell is incorporated in the system disclosed,it is not necessary to recalibrate the system or to return the system toa state of zero eccentricity or eliminate the lost motion before dial 72is turned to a new thickness setting. All that is necessary to positionthe electrode whether or not end dwell is utilized is to turn the dial72 to read the proper plate thickness. By this means, the center of themotor shaft is always brought to the proper position relatively to thereference plane required by the plate thickness to which the dial 72 isset and all oscillations of the electrode will be centered about thecenter of the plate, whether or not end dwell is set up by thepositioning of the cam followers 58, 60.

Summarizing, the dial 72 having once been calibrated properly need onlybe set to read the thickness of workpiece plate that is to be welded,with the result that the oscillations of the electrode tip 56 willautomatically be centered with reference to the thickness dimension ofthe workpiece plates. The desired amplitude of oscillation of theelectrode tip may then be set by turning the cam 44 relatively to thecam 42 to the desired amplitude as indicated by a suitable scale markedfor example on the face of the cam 44 or on the plate attached theretoto be aligned with an index mark scribed on the cam 42. The scale ispreferably calibrated to amplitude by decimal parts of inches. It willbe evident that the amplitude of the electrode oscillation should not beset so great as to exceed the limits of the thickness of the workpieceplates or molten material may be spilled or the electrode tip may strikesome portion of the framework to cause an are or other damage.

The bearing surfaces of the cam followers 58 and 60 are preferably madeaccurately parallel to each other. This is particularly important whenend dwell is not to be utilized. In the latter case, if these surfacesare not parallel, the cam 44, whose outer surface is circular will notcontact both cam followers continuously in the region where the distancebetween the cam followers is greater than the diameter of the cam 44,and will jam in the region where the distance between the cam followersis less than the diameter of the cam 44.

It will be evident to those skilled in the art that the invention may beutilized in other embodiments than that shown herein. For example, thelectrode may be arranged to oscillate along the path or line of anoverlay to distribute metal evenly along such path. A reference point orplane may be established at one end of the path and the dial 72 may becalibrated to read directly the length of the overlay so that theoscillations will have as their center the midpoint of the length of theoverlay. It will also be evident that a wide variety of tools other thana welding electrode may be positioned and oscillated in like manner.

While illustrative forms of apparatus and methods in accordance with theinvention have been described and shown herein, it will be understoodthat numerous changes may be made without departing from the generalprinciples and scope of the invention.

What is claimed is:

1. In a tool oscillator, in combination, a framework, a guide memberattached to said framework and defining a substantially linear path oftravel for elements guided thereby, an oscillator motor mount guided bysaid guide member, a motor mounted upon said motor mount, ec centricmeans actuated by said motor to impart oscillat ing motion to the tool,means to move the said motor mount along said guide member to anydesired position along the said path of travel, means to indicatedisplacement of the said motor mount along said path of travel withreference to an arbitrary zero displacement, and gearing incorporated insaid displacement indicating means to make the indicated displacementtwice the actual displacement.

2. In an electrode oscillator for welding, in combination, a guidemember fixedly mounted with respect to a welding head, a welding damfixedly mounted with respect to said welding head, said guide memberbeing arranged to guide the motion of components guided thereby along apath of travel in a direction substantially perpendicular to the planeof a working surface of said welding dam, an oscillator motor mountguided by said guide member, a motor mounted upon said motor mount, aneccentric cam mounted upon the shaft of said motor, a slide carried bysaid guide member, cam followers mounted upon said slide fortransmitting oscillations from said cam to said slide with reference tothe position of the motor shaft on the said guide member, said camfollowers serving additionally to constrain the slide to follow alongthe guide member in response to movements of the said motor mount,electrode holding means fixedly attached to and movable with said slide,means to move the said motor mount to any desired position along thesaid path of travel, and means to indicate an arbitrary reference pointalong the said path of travel corresponding to the condition in which anelectrode in said electrode holding means is in the plane of the saidworking face of the welding dam when said eccentric cam is in itsconcentric position.

3. In an electrode oscillator for welding, in combination, a guidemember fixedly mounted with respect to a welding head, a welding damfixedly mounted with respect to said welding head, said guide memberbeing arranged to guide the motion of components guided thereby along apath of travel in a direction substantially perpendicular 7 to a workingsurface ofsaid welding darn, an oscillator motor mount guided by saidguide member, a motor mounted upon said motor mount, an eccentric cammounted upon the shaft of said motor, a slider carried by said guidemember, atleast one cam follower mounted upon said slider fortransmitting oscillations from said cam to said slider with reference tothe position-of the motor shaft onthesaid guide member, said camfollower serving additionally to constrain theslider to follow along theguide member in responseto movements of the said motor mount, electrode"holding means fixedly attached to and movable with said slider, a leadscrew for moving said motor mount to any desired position alongsaidzpath of travel, a position indicating dialand gearing connectingsaid dial to said lead screw, the combination of the pitch of said leadscrew, said'gcaring andzsaid dial determining for motion in :thedirection substantially perpendicular ,to

one side of the workpiece plate-when saidplate is clamped between saidfirst and secondwelding :dams, calibratable 8 means toindicateltheposition of aapointin the non-oscililating portionof saidelectrode oscillating mechanism with :respect to said side of theclamped workpiece .plate, whereby the centerof oscillation ofanarc-electrode may :be setat:anyt-desired'distance from said sideof theclamped workpiece ,plate -to coincide with the center ofthickness of aworkpiece plate-of any agivcn thickness within a predetermined range ,ofworkpiece thicknesses.

5. Apparatus according-to claim {4, together-with indicia injuxtaposition on said-oscillatingportion and on said non-oscillatingportion'tof said electrode oscillating mechanism, whereby-the saidoscillating: portion ,may be brought to the central ,positionofoscillation :withrespect .to the said nomoscillating portion :byaligning-respective indicia of the said two portions.

6. Apparatus according to claim 1,-together with means {to adjust theilocationof'the said arbitrary zero displacementzrelatively toisaid pathoftravel.

ReferenceszCited by the Examiner UNITED STATES PATENTS I Var-s 219-l25RICHARD WOOD, Primary Examiner.

1. IN A TOOL OSCILLATOR, IN COMBINATION, A FRAMEWORK, A GUIDE MEMBERATTACHED TO SAID FRAMEWORK AND DEFINING A SUBSTANTIALLY LINEAR PATH OFTRAVEL FOR ELEMENTS GUIDED THEREBY, AN OSCILLATOR MOTOR MOUNT GUIDED BYSAID GUIDE MEMBER, A MOTOR MOUNTED UPON SAID MOTOR MOUNT, ECCENTRICMEANS ACTUATED BY SAID MOTOR TO IMPART OSCILLATING MOTION TO THE TOOL,MEANS TO MOVE THE SAID MOTOR MOUNT ALONG SAID GUIDE MEMBER TO ANYDESIRED POSITION ALONG THE SAID PATH OF TRAVEL, MEANS TO INDICATEDISPLACEMENT OF THE SAID MOTOR MOUNT ALONG SAID PATH OF TRAVEL WITHREFERENCE TO AN ARBITRARY ZERO DISPLACEMENT, AND GEARING INCORPORATED INSAID DISPLACEMENT INDICATING MEANS TO MAKE THE INDICATED DISPLACEMENTTWICE THE ACTUAL DISPLACEMENT.